European Heart Journal Advance Access originally published online on December 3, 2007
European Heart Journal 2008 29(1):139-140; doi:10.1093/eurheartj/ehm524
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Can prolonged exercise-induced myocardial ischaemia be innocuous? reply
Quebec Heart Institute/Laval Hospital
Laval University
2725 Chemin Ste-Foy
Ste-Foy
Quebec
Canada G1V 4G5
Quebec Heart Institute/Laval Hospital
Laval University
2725 Chemin Ste-Foy
Ste-Foy
Quebec
Canada G1V 4G5
Quebec Heart Institute/Laval Hospital
Laval University
2725 Chemin Ste-Foy
Ste-Foy
Quebec
Canada G1V 4G5
Quebec Heart Institute/Laval Hospital
Laval University
2725 Chemin Ste-Foy
Ste-Foy
Quebec
Canada G1V 4G5
Tel: +(418) 656 8711 Fax: +(514) 735 6634 Email: peter.bogaty{at}med.ulaval.ca
We appreciate Dr Fragasso's interest in our recent work.1 Fragasso et al.2 showed in patients with coronary disease a lowered left ventricular filling rate 2 days after exercise that was no longer significantly different from baseline at 7 days. Whether this is sufficient to support the notion that exercise-induced myocardial ischaemia in patients with stable coronary artery disease causes sustained clinically significant diastolic dysfunction cannot be certain. Importantly, the 15 patients in Dr Fragasso's study had severe coronary disease as evidenced by their poor exercise capacity (70 ± 30 W) that was less than half that of our patients (152 ± 56 W), their development of myocardial ischaemia at 217 ± 161 s of exercise compared with 442 ± 85 s for our patients and the lower rate-pressure product attained by their patients compared with ours (22 697 ± 5315 vs. 27 308 ± 7445 b.p.m. mmHg).
During a structured exercise training program above their myocardial ischaemic threshold, throughout serial evaluations, our patients had no troponin rises or significant arrhythmias and unchanged left ventricular systolic function. Nor did we observe any alteration of VO2max, a physiological variable closely related to cardiac function and most powerful predictor of mortality and morbidity.3 Because of the need for brevity, we did not report the spectral tissue Doppler echocardiography E/e1 ratio that was within normal range in the experimental group (15 ± 6). This ratio, derived from the septal annulus velocity, is known to have similar accuracy to B-type natriuretic peptide as a non-invasive surrogate for the diagnosis of diastolic function.4
Experimental models using brief intermittent coronary occlusion that show deleterious myocardial effects cannot necessarily be extrapolated to the human context of coronary disease and exercise-induced myocardial ischaemia.5 Nor is it characteristic of active patients with uncomplicated chronic stable angina and good ventricular systolic function who frequently have episodes of myocardial ischaemia (most often asymptomatic) in daily life, to evolve towards heart failure.6 Does this not in itself suggest that regular ischaemic episodes in such patients may not be deleterious? Notwithstanding our findings of the excellent tolerance and apparent innocuity of an ischaemic exercise program in our patients, we were careful to state the need for further studies in similar and other patient groups. We agree for the need for caution in this field but also believe that the door should not be shut on such explorations given the possible benefits of more intense exercise in patients with chronic stable ischaemic heart disease.
References
- Noel M, Jobin J, Marcoux A, Poirier P, Dagenais GR, Bogaty P. Can prolonged exercise-induced myocardial ischaemia be innocuous? Eur Heart J (2007) 28:1559–1565.
[Abstract/Free Full Text] - Fragasso G, Benti R, Sciammarella M, Rossetti E, Savi A, Gerundini P, Chierchia SL. Symptom-limited exercise testing causes sustained diastolic dysfunction in patients with coronary disease and low effort tolerance. J Am Coll Cardiol (1991) 17:1251–1255.[Abstract]
- Myers J, Prakash M, Froelicher V, Do D, Partington S, Atwood JE. Exercise capacity and mortality among men referred for exercise testing. N Engl J Med (2002) 346:793–801.
[Abstract/Free Full Text] - Arques S, Roux E, Luccioni R. Current clinical applications of spectral tissue Doppler echocardiography (E/E' ratio) as a noninvasive surrogate for left ventricular diastolic pressures in the diagnosis of heart failure with preserved left ventricular systolic function. Cardiovascular Ultrasound (2007) 5:16.[CrossRef][Medline]
- Geft IL, Fishbein MC, Ninomiya K, Hashida J, Chaux E, Yano J, J YR, Genov T, Shell W, Ganz W. Intermittent brief periods of ischemia have a cumulative effect and may cause myocardial necrosis. Circulation (1982) 66:1150–1153.
[Abstract/Free Full Text] - Poole-Wilson PA, Voko Z, Kirwan BA, de Brouwer S, Dunselman PH, Lubsen J. Clinical course of isolated stable angina due to coronary heart disease. Eur Heart J (2007) 28:1928–1935.
[Abstract/Free Full Text]
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